There has been an industry trend from analog to digital modulation in communication systems. Some of the benefits of digital modulation include more robust communication, ability to introduce security through encryption/de-encryption, the ability to multiplex multiple forms of data (e.g., data, voice, video . . . ) and lower implementation costs, among others.
Digital modulation can be used to transfer digital serial data over an RF passband waveform. Modulation techniques include, but are not limited to, quadrature phase shift keying (QPSK), differential quadrature phase shift keying (DQPSK), frequency shift keying (FSK), minimum shift keying (MSK), quadrature amplitude modulation (QAM) and differential quadrature amplitude modulation (DQAM). Digital modulation is used in wireless and wired communication systems. Cellular, satellite, terrestrial and broadband cable systems represent examples of communication systems implementing digital modulation. Modulation can be implemented through IQ generation (e.g., channel coding) and digital modulation (e.g., RF synthesis or direct digital synthesis). The “I” represents the in phase component where the “Q” represents the quadrature component. IQ data can result in an IQ stream that can be switched to provide resiliency and support broadcast transmissions from a single generation point. In one implementation, IQ data can be packetized for switching while other implementations switching can be performed on non-packetized IQ data. One or more IQ streams can be combined in one implementation of a digital modulator to optimize the number of RF channels supported.
Like reference numbers and designations in the various drawings indicate like elements.